Lewis & Short

Histri (less correctly Istri), ōrum, m., the people of Istria, Istrians, a barbarous Illyrian tribe subdued by the Romans B. C. 177: principes Histrorum, Liv. 41, 11; Plin. 3, 19, 23, § 129: Histrorum gentem originem a Colchis ducere, Just. 32, 3, 13: per Histros Hister emittitur, Mel. 2, 3 fin.
Hence, Histria (Istria), ae, f., a country on the eastern shore of the Adriatic Sea, extending from Trieste to the Sinus Flanaticus: Histria ut peninsula excurrit, Plin. 3, 19, 23, § 129; Liv. 39, 55.
Derivv.

  1. A. Histriāni (Ist-), ōrum, m., the people of Istria, Just. 9, 2, 1.
  2. B. Histrĭ-cus (Ist-), a, um, adj., Istrian, of Istria: bellum, Liv. 39, 55; 41, 1; 11: ostrea, Plin. 32, 6, 21, § 62.
  3. C. Histrus, a, um, adj., Istrian: testa, Mart. 12, 64, 2.